Add option to reset personal note ("delete") at students view for class teachers

Class teachers (= primary group owners of a person) should be able to delete personal notes entries (= clear) for their students. (Wrongly added absences etc.)

changed milestone to %1.0a1

added part::backend part::frontend prio::1 source::customer type::feature labels

created merge request !86 (merged) to address this issue

mentioned in merge request !86 (merged)

assigned to @hansegucker

This MUST use reversion!

Good point

closed via merge request !86 (merged)

mentioned in commit 832a7d25